Heretofore, various color temperature variable illumination apparatuses in which the light color (color temperature) of the illumination light is adjustable have been provided, and an example thereof is disclosed in JP 2010-176986A (hereinafter referred to as “Document 1”). The color temperature variable illumination apparatus described in Document 1 includes an illumination light source including a plurality of light sources each having a different light color, and a drive means that causes each of the plurality of light sources to emit light individually and at an arbitrary light quantity. Also, the color temperature variable illumination apparatus includes a determination means that determines a light quantity of each of the light sources of the illumination light source such that the color temperature of the illumination light that is irradiated from the illumination light source will be a color temperature corresponding to an operation input that is received by a controller.
The drive means causes each of the light sources to emit light at the light quantity determined by the determination means. Also, the determination means determines the light quantity of each of the light sources such that the difference in a reciprocal color temperature of the illumination light corresponding to an amount of change in the operation input has a proportional relationship to the amount of change in the operation input. Accordingly, in this color temperature variable illumination apparatus, any feeling of unnaturalness regarding the change in the color temperature of the illumination light that is actually recognized relative to the change in the operation input is unlikely to arise.
Here, in general, when a lighting apparatus such as a color temperature variable illumination apparatus is activated, regardless of a value of light quantity and color temperature designated with a controller, an illumination light source is first lighted in an initial state, and is thereafter controlled such that illumination light becomes a designated light quantity and color temperature. The reason for this is to avoid the illumination light source being fully lighten momentarily when an input from the controller is delayed relative to the activation of the lighting apparatus.
However, with the conventional color temperature variable illumination apparatus described above, problems such as described below may arise. For example, in a case where a color temperature of 5000K is designated with the controller, the illumination light source is first lighted in an initial state when the apparatus is activated, and thereafter the illumination light source is controlled such that the color temperature of the illumination light becomes 5000K that is the target color temperature. That is, if the color temperature of the illumination light source in the initial state is assumed to be 2000K, the color temperature of the illumination light source changes from 2000K to 5000K. The color temperature of the illumination light source at the time of activation of the apparatus is thus different from the color temperature of the illumination light source expected by the user, and as a result the user may have a feeling of unnaturalness visually.